The JP Low Mass Operating System is designed for weapon systems that need to operate in top condition. The low mass carrier allows for a lighter recoil impulse, especially when your gas system is tuned correctly. For an aesthetically pleasing look and smooth finish, the carrier has been high polished for a slick action. Forward assist serrations have been included just in case you need them.

The LMOS is compatible with both DPMS and Armalite, but you should never mix the two types of parts when not buying a complete BCG.